Horizontal earth boring machine

ABSTRACT

A remote grade indiciating apparatus for machines for tunneling, jacking and boring into earth fill, such remote grade indicating apparatus permits the operator to accurately establish the grade inclination or declination at the outset of the boring operation and moreover to continuously monitor the grade angle being established as the boring operation progresses. More specifically, the remote grade indicating apparatus comprises a remote sensor mounting on the foremost casing portion driven into the earth fill and a read-out apparatus at the operator&#39;&#39;s station such that the operator can proceed with the earth boring operation in accordance with his continuous observation of the remote grade indicating apparatus.

Unite States atent 1 1 Barnes 1|; 3, 1974 [54] HORIZONTAL EARTH BORING MACHINE 3,767,836 10 1973 Geis et al 175/62 75 l ventor: Thomas W. Barnes Franklin, Ohio I 1 n Primary ExaminerFrank L. Abbott Asslgneei The Richmond q l' g Assistant Examiner-Richard E. Favreau p y, Ashland, 01110 Attorney, Agent, or Firm-Palmer Fultz, Esq. [22] Filed: Apr. 27, 1973 B T [21] Appl. No.: 354,998 [57] A STRAC A remote grade indiciating apparatus for machines for tunneling, jacking and boring into earth fill, such re- [52] [1.8. CI 175/45, 175/62, 33/367 mote grade indicating apparatus permits the operator [51] Int. Cl EZlb 47/02 to accurately establish the grade inclination or m [58] Field of Search 299/1; 175/45, 40, 62, nation at the outset of the boring operation and more 175/171; 173/20; 333/367 313 over to continuously monitor the grade angle being established as the boring operation progresses. More [56] References C'ted specifically, the remote grade indicating apparatus UNITED STATES PATENTS comprises a remote sensor mounting on the foremost 1,231,162 6/1917 Husby 33/367 Casing Portion driven into the earth fill and a read-Out 1,932,068 10/1933 Englebright 175/62 X apparatus at the operators station such that the oper- 2,664,645 1/1954 Qualman 33/367 ator can proceed with the earth boring operation in 3,107,74l l0/1963 Adams et a1 175/62 accordance with his continuous observation of there- 3,46l,979 8/1969 Nev/farmer 175/45 mote grade i i i apparatus 3,482,103 12/1969 Martinsen..... 299/1 X 3,651,581 3/1972 Lehman 33/367 16 Claims, 7 Drawing Figures 0 /fi"fi 57 26 22 l8 I2 44 204- 70 I9 29 30 14 3 A 56 2! Q I? 0L0 3 a I 3/ M l i a 1e ze-A t Pmmmi 31914 3.851.716

SHEEI 20F 3 FIG. 2.

6O 4/ WATER SUPPLY T SENSING MEANS I HORIZONTAL EARTH BORING MACHINE BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION In general, the typical. machine illustrated for use with the present invention comprises an earth boring machine which comprises a power means mounted on a track for longitudinal advancement towards the hole being bored. Such power means comprises both earth boring auger means and easing pusher ring means whereby the pusher ring can successively advance casing sections into the bored hole as the auger means progressively drills the hole.

As a primary aspect of the present invention the boring machine is provided with a novel remote grade indicating apparatus that continuously provides read-out to the machine operator with respect to the angle of inclination or declination of the front portion of the foremost casing section.

Such remote grade indicating apparatus comprises a sensing means mounted on the front portion of the foremost casing section, and a gauge means adjacent to the operators station at the power means with said gauge means being connected to said sensing means so as to provide constant read out with respect to changes in grade occurring at the forward end of the hole being bored.

In accordance with the present invention the above mentioned sensing means is provided with a novel arrangement for the temporary support of a sight target for zeroing said read-out gauge with the sensing means at the outset of the boring operation.

As another aspect of the present invention the abovementioned remote grade indicating apparatus, in combination with the above mentioned zeroing and sight target apparatus provide means for not only establishing but also returning to a zero grade reference when a boring and pushing operation is temporarily suspended with the power means temporarily removed to another location. Upon resuming of the suspended boring operation the power means and remote grade indicating apparatus can be accurately repositioned at the boring location with the same original zero for the sensing means and read-out gauge when the boring of the hole is continued.

It is therefore an object of the present invention to provide a novel remote grade indicating apparatus for a horizontal earth boring machine which uniquely includes a temporary sight target and read-out gauge arrangement for zeroing said gauge with a remote sensing means at the outset of the boring operation.

It is another object of the present invention to provide a horizontal earth boring machine and remote grade indicating apparatus adapted to be temporarily removed from an earth boring location during suspended boring operations, and subsequently returned to the same location with the capability of readily es- LII tablishing the same zero grade reference notwithstanding the bored hole and pushed casing sections are remotely disposed in the earth fill.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment is clearly shown.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a boring machine provided with the grade indicating apparatus of the I present invention;

FIGS. 2 and 2-A are front elevational views of a portion of a read-out device comprising a portion of the apparatus of the preceding figures;

FIG. 3 is a top elevational view of a sensor constructed in accordance with the present invention;

FIG. 4 is a side elevational view of the sensor of FIG.

FIG. 5 is a side diagrammatic view of the sensor of FIGS. 3 and 4 and showing such sensor in a declined indicating position; and

FIG. 6 is a side diagrammatic view of the sensor of FIGS. 3 and 4 and showing such sensor in an inclined indicating position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring in detail to the drawings an apparatus constructed in accordance with the present invention is shown in FIG. land includes a horizontal boring machine indicated generally at 12 which includes a track means 10 on which is mounted a carriage 24 for longitudinal movement along the track means.

Carriage 24 is advanced along the track means 10 by hydraulic pushing cylinders 11 with said cylinders having their rear ends connected to a pusher frame 16 and the forward ends connected to said carriage 24.

The pusher frame 16 comprises a latch mechanism, not illustrated, for locking it into engagement with track means 10 at various longitudinal positions. Such pusher frame 16 is disclosed and described in detail in U.S. Pat. No. 3,612,194. I

Carriage 24 supports the power means 12, which comprises an engine 14, a gear reduction unit 20 for driving boring auger sections, two of which are seen at 28 and 28-A, with the auger sections being joined at the junction 31, a hydraulic pump 17 for energizing pushing cylinders 11, and hydraulic control valve means 18 for selectively delivering pressurized fluid from pump 17 to either the extension end or retraction end of pushing cylinders 11. I

As is further seen in FIG. 1, track means 10 supports a pusher ring 22 which is connected to the power means by the thrust plates 25 such that when pushing cylinders 11 are energized to extend, then pusher ring 22 functions to advance casing sections 26 and 26-A through the earth fill 42.

Referring again to FIG. 1 boring of the hole is effected by the above mentioned auger sections'which are extended into the casing means and driven by the previously described power means 12.

As seen in FIG. 1, the foremost auger section 28 is provided with a cutting head 30 which serves to grind away the earth fill 42 such that the auger sections 28 and 28-A can continuously convey the ground-out earth fill rearwardly to pusher ring 22 where such ground-out earth fill is discharged laterally from an opening 21 in said pusher ring.

Reference is next made to the remote grade indicating apparatus of the present invention which is shown in assembled relationship with the boring machine in FIG. 1 and which comprises a sensing means indicated generally at 70 which is mounted on the foremost casing portion 26-A. The apparatus further. includes a gauge means indicated generally at 44 and shown in enlarged detail in FIG. 2, which gauge means is located at the operators station of the boring machine, as seen in FIG. 1, and serves to continuously provide read-out information with respect to deviation in the inclination or declination of the bored hole as the drilling operation progresses.

Referring in detail to FIG. 3, the sensing means 70 comprises a housing 72 preferably in the form of a solid metal block with drilled passages 84, 82, 80, and 81 forming an inverted generally U-shaped fluid passage connecting an inlet 78 with an outlet 86.

With continued reference to FIGS. 3 and 4, the main housing 72 is provided with a cap 74 attached by welds 76 with such cap being provided merely for the purpose of facilitating the forming of the above mentioned passages.

As seen in FIGS. 3-6, the sensing means 70 includes laterially extending shoulders 90 and 92 in the form of metal pins which are merely provided so as to form a temporary support for a sight target which is shown in the form of a conventional surveyor stake 98 with such sight target being utilized by the operator at the outset of the boring operation for the purpose of zeroing the apparatus in a manner later to be described.

Referring in detail to FIGS. 1, 2, and 2A, the remote sensing apparatus further includes a gauge means indicated generally at 44 that includes a transparent tube 48 mounted on a frame 46 in overlying relationship with an indicia scale 50 which includes the zero base and the related indicia marks which divides the scale into units, for example one-hundredths of a foot.

Gauge means 44 communicates with a water supply 40 via a tube 41 which enters a valve 60 leading to fitting 52.

' The apparatus further includes a bleed-off valve 64, a bleed offtube 58, and avalve 66 communicating with tube 56 that in turn is connected to the previously described sensing means 70.

The system is charged from supply 40 through open valves 60, 64, 66, and 62. Valve 64 is closed when line 41 is full and free of air. Valve 66 is next closed and valve 62 is closed when transparent tube 48 is full.

Valves 66 and 62 are next opened and the water will seek its level in transparent tube 48 as dictated by the vertical location of sensing means 70.

In the event the boring is being conducted at a declined angle the water level 100 will be established at the top of rightreference pin 90 since water can bleed out of sensor outlet 86 until such level is established as seen in FIG. 5.

When the boring operation is being conducted at an inclined angle, as seen in FIG. 6, then the water level in gauge tube 48 will correspond with the top of reference pin 92.

At the outset of the boring operation, before foremost casing section '26-A, and the gauge 70 mounted thereon, are buried in the earth fill, the apparatus is zemark on the surveyors stake 98. The surveyors stake is then removed after zeroing the apparatus and the drilling and pushing operations are next commenced.-

It should be mentioned that outlet 86 of the sensing means is superimposed over a drain hole 19, FIG. 1, through the wall of casing section 26A to provide means for releasing water from outlet 86.

It will now be understood that after sensing means 70 disappears into the earth fill, as seen in FIG. I, the zero grade position of the foremost casing portion 26-A will be present when the water level is at the zero mark on the indicia scale of gauge 44. Moreover, as the foremost casing portion inclines or declines the exact amount of such angular change will be reflected by the water level in the transparent tube 48 of the gauge.

It should further be mentioned that in instances where the boring apparatus and associated grade indicating apparatus are to be temporarily removed from the earth fill and it is desired to come back to the job and re-operate the apparatus at the same reference, then in such instances a reference means bench mark 200 can be driven into the earth fill adjacent to the gauge as seen in FIG. 1 and the location of the zero reference on the gauge can be noted on the bench mark using a surveyors transit 204 as a sighting means with such bench mark left in the boring bed when the apparatus is temporarily removed therefrom. When the apparatus is returned, the operator merely needs to line up the zero on the gauge 44 with the mark location on the bench mark using the transit 204 and the boring operation can be resumed with the same zero reference with respect to grade deviations.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

I claim:' 1

1. A remote grade indicating apparatus for tunneling, jacking and boring into earth fill in the construction of subterranean passages, said apparatus comprising, in combination, sensing means for progressive extension into the earth fill; gauge means for location adjacent the earth fill and connected to the sensing means, said gauge means including read-out indicia for informing the operator of grade deviations of the sensing means; and means forming a shoulder on the sensing means for temporary support of a sight target for zeroing the gauge means with the sensing means at the outset of the progression into the earth fill.

2. The apparatus defined in claim 1 that includes a zero reference stake located adjacent said gauge means for relocation of said gauge means after it has been temporarily removed from its location adjacentthe earth fill.

3. A remote grade indicatingapparatus for tunneling, jacking and boring into earth fill in the construction of subterranean passages, said apparatus comprising, in combination, sensing means for progressive extension into the earth fill and including an inverted generally U-shaped fluid passage having a sensing means outlet; gauge means for location adjacent the earth fill and connected to the sensing means, said gauge means including read-out indicia responsive to the level of fluid in said fluid passage for informing the operator of grade deviations of the sensing means; and means forming a shoulder on the sensing means for temporary support of a sight target for zeroing the gauge meanswith the sensing means at the outset of the progression into the earth fill.

4. A remote grade indicating apparatus for tunneling, jacking, and boring into earth fill in the construction of subterranean passages, said apparatus comprising, in combination, sensing means for progressive extension into the earth fill and including a fluid passage for establishing a fluid level corresponding with grade deviations of the progression'into the earth fill; gauge means for observation by the boring machineoperato'r and including a gauge.'tubecommunicating with said fluid passage and containing a fluid, said gauge tube being provided with indicia, the level of the fluid in said gauge tube corresponding with said fluid level in said sensing means; and means forming a shoulder on said sensing means for the temporary support-of a sight target for zeroing. said gauge means with said sensing means at the outset of progression into the earth till.

5. The apparatus defined in-claim 4 wherein said fluid passage is of inverted generally U-shaped configuration;

6. A machine for conducting operations within an earth fill comprising, in combination, an apparatus for progressive extension into said earth fill; sensing means mounted on said apparatus; gauge means for location in said sensing means; and means forming a shoulder on said apparatus for the support of a sight target for zeroing said gauge means with said sensing means at the outset of progression into the earth fill.

10. The apparatus defined in claim 9 wherein said fluid passage is of inverted generally U-shaped configuration.

11. A horizontal earth boring apparatus comprising, in combination, track means; power means mounted on said track means for longitudinal advancement thereon, said power means including a casing pusher ring; casing means including a rear casing end portion engaged by said pusher ring and a front casing end portion; auger means extended into said casing means and including a rear auger end driven by said power means and a front auger end portion; sensing means mounted on said front casing portion for extension into the earth 'fill therewith; gauge means adjacent said power means and connected to said sensing means and provided with adjacent the earth fill and connected to the sensing means, said gauge means including read-out indicia for informing the operator of grade deviations of the sensing means; and means forming a shoulderon the sensing means for temporary support of a sight target for zeroing the gauge means with the sensing means at the outset of the progression into the earth fill. a

7. The apparatus defined in claim 6 that includes a zero reference stake located adjacent said gauge means for relocation of said-gaugemeans afterit has been temporarily removed from its location adjacent the earthfill. v r

8.A machine for conducting operations within an earth fillcomprising, in combination, an apparatus for progressive extension into'saidearth fill; sensing means mounted on said apparatus and including an inverted generally U-shaped fluid passage having a sensing means-outlet; gauge means for location adjacent the earth fill and connected tothe sensing means, said gauge means including read-out indicia responsive to the level ofsfluid in said fluid passage for informing the operator of grade deviations of the sensing means; and

, means forming a shoulder on the sensing means for temporary support of a sight target for zeroing the gauge means'with the sensing means at the outset of the progression into the'earth fill.

read-out indicia for informing the operator of grade de- I viations of said front casing end portion; means forming a shoulder on said sensing means for thetemporary support of a sight target for zeroing said gauge means with said sensing means at the outsetof the boring operation; and'reference means mountable on the earth fill adjacent the gauge means for establishing a stationary reference for the zero of said gauge means.

12. A horizontal earthboring apparatus comprising in combination, track means; power means mounted on said track means for longitudinal advancement thereon,'said power means including a casing pusher ring; casing means including a rear casing end portion engaged by said pusher ring and a front casing end portion; auger means extended into said-casing meansand including a rear auger end driven by said power means and a front auger end portion; sensing means mounted on said front casing portion and including a sensing means housing provided with an-inverted generally U- shaped fluid passage having a sensing means outlet; gauge means adjacent said power means and provided withread-out indicia responsive to the'level of fluid in said fluid passage;-and means forming a shoulder on 9. A machine for cond ucting operations within an earth fill comprising, in combination, anta'pparatus for progressive extension into said earth fill; sensing means mounted on said apparatus and including a 'fluid passage' for establishing a'fluid levefcorrespondingwith grade deviations-of the progression into the earth fill; gauge means for observation by the boring machine operator and including a gauge tube communicating with said fluid passage and containing a fluid, said gauge tube being provided with indicia, the level of the fluid in said gauge tube corresponding with said fluid level said sensing means forthe temporary support of a sight target for zeroing said gauge means with said sensing means at the outset of the boring operation.

13. A horizontal earth boring apparatus comprising, in combination, track means; power means mounted on said track means for longitudinal advancement,

thereon, said power means including a casing pusher engaged by said pusher ring and a front casing end porring; casing'means including a rear casing end portion tion; auger means extended into said casing means and including 'a rear'auge'r end drivenby saidpower means and a front auger end portion; sensing means mounted on said front casing portion for extension 'into the earth fill therewith; gauge means adjacent said power means and connected to said sensing means and provided with read-out indicia for informing the operator of grade deviations of said frontcasing end portion;'and pin means on said sensing means for'the temporary support of a sight target for zeroing said gauge meanswithsaid sensing-means at the outset of said boring operation.

14. A horizontal'earth boring apparatus'comprising, in combination, track means; power means mounted on said track means for longitudinal advancement thereon, said power means including-a casing pusher ring; casing means including a rear casing end portion 7 engaged by said pusher ring and a front casing end portion; auger means extended into said casing means and including a rear auger end driven by said power means and a front auger end portion; sensing means mounted on said front casing portion and including a sensing means housing provided with an inverted generally U- shaped fluid passage having a sensing means outlet;

gauge means adjacent said power means and provided with read-out indicia responsive to the level of fluid in said fluid passage; and pin means on said sensing means for the temporary support of a sight target for zeroing said gauge means with said sensing means at the outset of said boring operation.

, 15. A horizontal earth boring apparatus comprising, in combination, track means; power means mounted on said track means for longitudinal advancement thereon, said power means including a casing pusher ring; casing means including a rear casing end portion engaged by said pusher ring and a front casing end portion; auger means extended into said casing means and including a rear auger end driven by saidpower means and a front auger end portion; sensing means mounted on said front casing portion and including a fluid'passage for establishing a fluid level corresponding with grade deviations of said front casing end portion; gauge means for observation by the boring machine operator and including a gauge tube containing a fluid and indicia, the level of the fluid in said gauge tube corresponding with said fluidlevel in said sensing means; and means forming a shoulder on said sensing means for the temporary support of a sight target for zeroing said gauge means with said sensing means at the outset of the boring operation.

16. A horizontal earth boring apparatus comprising, in combination, track means; power means mounted on said track means for longitudinal advancement thereon, said power means including a casing pusher ring; casing means including a rear casing end portion engaged by said pusher ring and a front casing end portion; auger'meansextended into said casing means and including a rear auger end driven by said power means and a front auger end portion; sensing means mounted on said front casing portion and including a fluid passage for establishing a fluid level corresponding with grade deviations of said front casing end portion; gauge means for observation by the boring machine operator and including a gauge tube communicating with said fluid passage and containing a fluid, the level of the fluid in said gauge tube corresponding with said fluid level in said sensing means; and pin means on said sensing means for the temporary support of a sight target forzeroing said gauge means with said sensing means at the outset of said boringoperation. 

1. A remote grade indicating apparatus for tunneling, jacking and boring into earth fill in the construction of subterranean passages, said apparatus comprising, in combination, sensing means for progressive extension into the earth fill; gauge means for location adjacent the earth fill and connected to the sensing means, said gauge means including read-out indicia for informing the operator of grade deviations of the sensing means; and means forming a shoulder on the sensing means for temporary support of a sight target for zeroing the gauge means with the sensing means at the outset of the progression into the earth fill.
 2. The apparatus defined in claim 1 that includes a zero reference stake located adjacent said gauge means for relocation of said gauge means after it has been temporarily removed from its location adjacent the earth fill.
 3. A remote grade indicating apparatus for tunneling, jacking and boring into earth fill in the construction of subterranean passages, said apparatus comprising, in combination, sensing means for progressive extension into the earth fill and including an inverted generally U-shaped fluid passage having a sensing means outlet; gauge means for location adjacent the earth fill and connected to the sensing means, said gauge means including read-out indicia responsive to the level of fluid in said fluid passage for informing the operator of grade deviations of the sensing means; and means forming a shoulder on the sensing means for temporary support of a sight target for zeroing the gauge means with the sensing means at the outset of the progression into the earth fill.
 4. A remote grade indicating apparatus for tunneling, jacking, and boring into earth fill in the construction of subterranean passages, said apparatus comprising, in combination, sensing means for progressive extension into the earth fill and including a fluid passage for establishing a fluid level corresponding with grade deviations of the progression into the earth fill; gauge means for observation by the boring machine operator and including a gauge tube communicating with said fluid passage and containing a fluid, said gauge tube being provided with indicia, the level of the fluid in said gauge tube corresponding with said fluid level in said sensing means; and means forming a shoulder on said sensing means for the temporary support of a sight target for zeroing said gauge means with said sensing means at the outset of progression into the earth fill.
 5. The apparatus defined in claim 4 wherein said fluid passage is of inverted generally U-shaped configuration.
 6. A machine for conducting operations within an earth fill comprising, in combination, an apparatus for progressive extension into said earth fill; sensing means mounted on said apparatus; gauge means for locatIon adjacent the earth fill and connected to the sensing means, said gauge means including read-out indicia for informing the operator of grade deviations of the sensing means; and means forming a shoulder on the sensing means for temporary support of a sight target for zeroing the gauge means with the sensing means at the outset of the progression into the earth fill.
 7. The apparatus defined in claim 6 that includes a zero reference stake located adjacent said gauge means for relocation of said gauge means after it has been temporarily removed from its location adjacent the earth fill.
 8. A machine for conducting operations within an earth fill comprising, in combination, an apparatus for progressive extension into said earth fill; sensing means mounted on said apparatus and including an inverted generally U-shaped fluid passage having a sensing means outlet; gauge means for location adjacent the earth fill and connected to the sensing means, said gauge means including read-out indicia responsive to the level of fluid in said fluid passage for informing the operator of grade deviations of the sensing means; and means forming a shoulder on the sensing means for temporary support of a sight target for zeroing the gauge means with the sensing means at the outset of the progression into the earth fill.
 9. A machine for conducting operations within an earth fill comprising, in combination, an apparatus for progressive extension into said earth fill; sensing means mounted on said apparatus and including a fluid passage for establishing a fluid level corresponding with grade deviations of the progression into the earth fill; gauge means for observation by the boring machine operator and including a gauge tube communicating with said fluid passage and containing a fluid, said gauge tube being provided with indicia, the level of the fluid in said gauge tube corresponding with said fluid level in said sensing means; and means forming a shoulder on said apparatus for the support of a sight target for zeroing said gauge means with said sensing means at the outset of progression into the earth fill.
 10. The apparatus defined in claim 9 wherein said fluid passage is of inverted generally U-shaped configuration.
 11. A horizontal earth boring apparatus comprising, in combination, track means; power means mounted on said track means for longitudinal advancement thereon, said power means including a casing pusher ring; casing means including a rear casing end portion engaged by said pusher ring and a front casing end portion; auger means extended into said casing means and including a rear auger end driven by said power means and a front auger end portion; sensing means mounted on said front casing portion for extension into the earth fill therewith; gauge means adjacent said power means and connected to said sensing means and provided with read-out indicia for informing the operator of grade deviations of said front casing end portion; means forming a shoulder on said sensing means for the temporary support of a sight target for zeroing said gauge means with said sensing means at the outset of the boring operation; and reference means mountable on the earth fill adjacent the gauge means for establishing a stationary reference for the zero of said gauge means.
 12. A horizontal earth boring apparatus comprising in combination, track means; power means mounted on said track means for longitudinal advancement thereon, said power means including a casing pusher ring; casing means including a rear casing end portion engaged by said pusher ring and a front casing end portion; auger means extended into said casing means and including a rear auger end driven by said power means and a front auger end portion; sensing means mounted on said front casing portion and including a sensing means housing provided with an inverted generally U-shaped fluid passage having a sensing means outlet; gauge means adjacent said power means and provided with read-out indicia responsive tO the level of fluid in said fluid passage; and means forming a shoulder on said sensing means for the temporary support of a sight target for zeroing said gauge means with said sensing means at the outset of the boring operation.
 13. A horizontal earth boring apparatus comprising, in combination, track means; power means mounted on said track means for longitudinal advancement thereon, said power means including a casing pusher ring; casing means including a rear casing end portion engaged by said pusher ring and a front casing end portion; auger means extended into said casing means and including a rear auger end driven by said power means and a front auger end portion; sensing means mounted on said front casing portion for extension into the earth fill therewith; gauge means adjacent said power means and connected to said sensing means and provided with read-out indicia for informing the operator of grade deviations of said front casing end portion; and pin means on said sensing means for the temporary support of a sight target for zeroing said gauge means with said sensing means at the outset of said boring operation.
 14. A horizontal earth boring apparatus comprising, in combination, track means; power means mounted on said track means for longitudinal advancement thereon, said power means including a casing pusher ring; casing means including a rear casing end portion engaged by said pusher ring and a front casing end portion; auger means extended into said casing means and including a rear auger end driven by said power means and a front auger end portion; sensing means mounted on said front casing portion and including a sensing means housing provided with an inverted generally U-shaped fluid passage having a sensing means outlet; gauge means adjacent said power means and provided with read-out indicia responsive to the level of fluid in said fluid passage; and pin means on said sensing means for the temporary support of a sight target for zeroing said gauge means with said sensing means at the outset of said boring operation.
 15. A horizontal earth boring apparatus comprising, in combination, track means; power means mounted on said track means for longitudinal advancement thereon, said power means including a casing pusher ring; casing means including a rear casing end portion engaged by said pusher ring and a front casing end portion; auger means extended into said casing means and including a rear auger end driven by said power means and a front auger end portion; sensing means mounted on said front casing portion and including a fluid passage for establishing a fluid level corresponding with grade deviations of said front casing end portion; gauge means for observation by the boring machine operator and including a gauge tube containing a fluid and indicia, the level of the fluid in said gauge tube corresponding with said fluid level in said sensing means; and means forming a shoulder on said sensing means for the temporary support of a sight target for zeroing said gauge means with said sensing means at the outset of the boring operation.
 16. A horizontal earth boring apparatus comprising, in combination, track means; power means mounted on said track means for longitudinal advancement thereon, said power means including a casing pusher ring; casing means including a rear casing end portion engaged by said pusher ring and a front casing end portion; auger means extended into said casing means and including a rear auger end driven by said power means and a front auger end portion; sensing means mounted on said front casing portion and including a fluid passage for establishing a fluid level corresponding with grade deviations of said front casing end portion; gauge means for observation by the boring machine operator and including a gauge tube communicating with said fluid passage and containing a fluid, the level of the fluid in said gauge tube corresponding with said fluid level in said sensing means; and pin means on said sensing means foR the temporary support of a sight target for zeroing said gauge means with said sensing means at the outset of said boring operation. 